This invention relates to an improved discharge assembly for liquid manure spreaders. To be useful, a spreader of liquid manure must be able to handle a product containing solid vegetable waste material in the form of a thick slurry. Additionally, the liquid manure may include straw, grass and hay particles. It is important that the spreader distribute this slurry evenly on a field and that the spreading mechanism does not become clogged during use.
Several approaches have been tried. The U.S. Patent to Vaughn (U.S. Pat. No. 3,420,452) shows one approach. Vaughn discloses a cylindrical tank mounted on its side on a tractor drawn trailer chassis. The power takeoff from the tractor is coupled to a shaft which penetrates the front end of the tank near the bottom. The shaft runs the length of the tank leaving at the lower rear wall where it serves as the drive for a centrifugal pump. That portion of the shaft on the inside of the tank includes an auger shaped mechanism for continuously stirring the liquid manure slurry. The tank is filled by means of a hatch on the top of the tank. A discharge port near the bottom of the rear end wall of the tank allows liquid manure to enter the centrifugal pump. The blades of the impeller of the pump sweep liquid manure up along the side of the pump housing to a discharge aperature covered by an operator actuated gate valve. The liquid manure is ejected transversely of the path being followed by the tractor drawn spreader. The manure is flung by the impeller a considerable distance in an arc away from the aperture in the pump housing.
The U.S. Patent to Hodgson (U.S. Pat. No. 4,056,226) is an example of another type of liquid manure spreader. In the Hodgson system, the liquid maure slurry is carried in a mobile tank from which it may be discharged either through a nozzle or through soil injectors directly into the ground. The nozzle assembly includes a tubular body with a restricted end portion, plus a bracket upon which a nozzle closure is pivotally mounted. Pressure from a pump forces liquid against the pivotally mounted closure, causing it to swing outward and downward, thereby acting as a spray plate to spread the discharging liquid in a fan-like pattern about the nozzle.
Neither of the above spreaders provide the even distribution of liquid manure achieved with my invention. With my invention, liquid manure is discharged outwardly to the rear of the spreader in a fan-like pattern. By controlling the quantity of liquid discharged as a function of the angle off spreader centerline, the manure is spread evenly across the entire width of the path.